python——返回一個(gè)view對(duì)象，key的列表

d = {1:"one", 2:"two", 3:"three"}

for key, value in d.viewitems():

    print "%s - %s" % (key, value)

#1 - one

#2 - two

#3 - three

　　　　viewkeys()　　---返回一個(gè)view對(duì)象，key的列表